Extra 240V socket in parallel?

Reply

  #1  
Old 07-09-18, 09:53 AM
M
Member
Thread Starter
Join Date: Apr 2016
Location: USA
Posts: 28
Received 0 Votes on 0 Posts
Extra 240V socket in parallel?

Hi
We had a leak at home which destroyed our floors and kitchen. We are now trying to lay out a new kitchen.
Previously we had a range with an electric oven and a gas cooktop. The oven was fed from a 240V socket. I believe the breaker is a 40A

For the refit we want a built-in double electric oven, roughly where the range was.
But we want an induction cooktop on the other side of the (small) kitchen). We had induction back in the UK and it was awesome.

The kitchen planner has overlooked the fact there is no 240V socket on that side. The hobs can pull 8kW, so we're talking over 30A max for that appliance.

Providing the breaker and cables can take the current of both cooktop AND oven, can we channel the concrete and lay conduit under the kitchen floor to add the cooktop socket in parallel with the oven? The concrete is not pre-stressed etc, just regular slab pour.

Thanks
 
Attached Images  
Sponsored Links
  #2  
Old 07-09-18, 11:03 AM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 59,709
Received 1,176 Votes on 1,090 Posts
Your current circuit of 40A cannot run both so you need to start the planning process for adding a new circuit. I'm guessing you're on a slab. Where's the electric panel ?
 
  #3  
Old 07-09-18, 01:41 PM
Andrew's Avatar
Member
Join Date: Apr 2003
Location: USA
Posts: 1,015
Received 14 Votes on 10 Posts
What is a hob? Not familiar with that term.
Thanks,
Andy
 
  #4  
Old 07-09-18, 02:05 PM
A
Member
Join Date: Mar 2010
Location: USA
Posts: 4,154
Received 86 Votes on 80 Posts
Each unit (stove, oven, etc.) must have its own (240 volt) branch circuit.

The appliance's plug implies the maximum branch circuit amperage if the instructions or name plate does not already state that amperage.

The matching receptacle must be on a branch circuit with a matching or compatible amperage rating; for most ratings above 20 amps there is only one amperage rating allowed for each kind of receptacle. (I don't have the table of the NEC giving these ratings handy now but I do know that small items and appliances drawing less than 15 amps can and must be safely usable on 20 amp circuits.)

Most appliances (and tools) requiring more than 20 amps will draw more than half of the circuit rating.

So in most cases it is impossible for one branch circuit to serve more than one of these appiainces.
 
  #5  
Old 07-09-18, 02:08 PM
M
Member
Thread Starter
Join Date: Apr 2016
Location: USA
Posts: 28
Received 0 Votes on 0 Posts
Actually I rechecked the fuse panel and its 80A (40A per phase).
The slab is the basic deal I believe.
The fuse panel is the opposite side of the house. Maybe 40 feet away.
The fuse panel itself is only 2 years old as it was fitted when we had solar.

Hob is a cooktop. It's a British thing.
 
  #6  
Old 07-09-18, 02:40 PM
ray2047's Avatar
Member
Join Date: Mar 2006
Location: USA
Posts: 33,583
Received 13 Votes on 11 Posts
I rechecked the fuse panel and its 80A (40A per phase).
No, it is 40 amps. The poles aren't added together.
 
  #7  
Old 07-09-18, 02:50 PM
M
Member
Thread Starter
Join Date: Apr 2016
Location: USA
Posts: 28
Received 0 Votes on 0 Posts
Thanks for clarifying.
So the next question is... can a cable be run in metal conduit all around the outside of the house?
Otherwise we'd have to remove ceilings etc.

Alternatively we have to ditch the induction hob and get the gas line extended under the slab to a new place. Which sounds easy. In my head :-)
 
  #8  
Old 07-09-18, 03:21 PM
ray2047's Avatar
Member
Join Date: Mar 2006
Location: USA
Posts: 33,583
Received 13 Votes on 11 Posts
can a cable be run in metal conduit all around the outside of the house?
That is a common way. You could also use PVC and bury it.

As PCBoss says you can only use some cables such as. UF-b. However easier to pull would be individual conductors such as THWN. UF-b would be a bear to pull.
 

Last edited by ray2047; 07-09-18 at 09:02 PM.
  #9  
Old 07-09-18, 07:33 PM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 15,174
Received 92 Votes on 79 Posts
Some cables cannot be used outside even if in conduit .
 
  #10  
Old 07-10-18, 11:29 AM
M
Member
Thread Starter
Join Date: Apr 2016
Location: USA
Posts: 28
Received 0 Votes on 0 Posts
Thanks again guys.
So I'm looking to run 4wires of THHN 8 gauge in conduit around the outside of the house.
Can I use PVC SCH40 pipe? Or does it have to be metal?
 
  #11  
Old 07-10-18, 11:40 AM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 15,174
Received 92 Votes on 79 Posts
PVC is allowed for use outside by the NEC.
 
  #12  
Old 07-10-18, 12:23 PM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: United States
Posts: 10,700
Received 92 Votes on 82 Posts
The fuse panel is the opposite side of the house. Maybe 40 feet away.
The fuse panel itself is only 2 years old as it was fitted when we had solar.

I hope you meant the circuit breaker panel and not fuse panel. I haven't even seen a new fuse panel in close to 40 years.
 
  #13  
Old 07-11-18, 03:28 PM
P
Member
Join Date: Feb 2016
Location: United States, Virginia
Posts: 1,477
Received 111 Votes on 87 Posts
PVC can be sch40 if not subject to possible damage. If subject to possible damage it needs to be sch80.
 
Reply
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: